Visible Light Luminescence in Silica-Based Superstructure Films

We measured the visible luminescence, under various conditions, of two different silica based superstructure films mounted on a silica substrate. One superstructure film was made up of alternate nanometer layers of Ge:SiO 2 , Ti:SiO 2 and Sn:SiO 2 and the other of Ge:SiO 2 , Ti:SiO 2 and Zr:SiO 2 . We used UV irradiation (wavelength: 254 nm) to cause the luminescence. The luminescent color changed depending on the doping material. The luminescent intensity increased as samples were cooled from room temperature to −196 °C, and luminescence disappeared in samples heated to 150 °C. Further investigation of the silica based superstructure film will likely lead to a new optical material.